+1 for a jaunt around Norfolk. We stayed at Wells YHA some years ago and it was good. Lots of decent lanes around, and even the "main" coast road isn't too busy by our normal standards.
If you have a few hours to spare in the Blakeney area then I recommend the seal watching trips, usually from Morston Quay - they should be running in November.
Our "mini tour" route was Day1 train to Norwich, cycle to Sheringham, Day2 Seal watching, short ride to Wells, Day3 cycle back to Norwich for train home (we did go via a short section at the Norwich end of the Marriotts way and I don't remember anything terribly bad happening!)